<template>
  <div class="app-container">
    <!-- App.vue分三部分,上面的header,中间的router-view,下面的navbar -->
    <mt-header fixed title="黑马程序员·vue">
      <span slot="left">
        <mt-button icon="back" @click="back" v-show="flag">返回</mt-button>
      </span>
    </mt-header>
    <div class="main">
      <transition>
        <router-view></router-view>
      </transition>
    </div>
    <!-- tabbar区域 -->
    <nav class="mui-bar mui-bar-tab">
      <router-link class="my-tab-item" to="/home">
        <span class="mui-icon mui-icon-home"></span>
        <span class="mui-tab-label">首页</span>
      </router-link>
      <router-link class="my-tab-item" to="/member">
        <span class="mui-icon mui-icon-contact"></span>
        <span class="mui-tab-label">会员</span>
      </router-link>
      <router-link class="my-tab-item" to="/chart">
        <span class="mui-icon mui-icon-extra mui-icon-extra-cart">
          <span class="mui-badge" id="badge">{{ $store.getters.gettotalcount }}</span>
        </span>
        <span class="mui-tab-label">购物车</span>
      </router-link>
      <router-link class="my-tab-item" to="/search">
        <span class="mui-icon mui-icon-search"></span>
        <span class="mui-tab-label">搜索</span>
      </router-link>
    </nav>
  </div>
</template>

<script>
export default {
  data() {
    return {
      flag: false
    };
  },
  created() {
    // 初始化的时候如果当前路径是home,就不显示返回按钮,否则显示返回按钮
    this.flag = this.$route.path === "/home" ? false : true;
  },
  methods: {
    back() {
      // 返回上一个链接
      this.$router.go(-1);
    }
  },
  watch: {
    // 监听路由地址的变化,如果当前路由链接是home,就不显示返回按钮
    "$route.path": function(newval) {
      if (newval === "/home") {
        this.flag = false;
      } else {
        this.flag = true;
      }
    }
  }
};
</script>
<style lang="scss" scoped>
.app-container {
  padding-top: 40px;
  padding-bottom: 50px;
  // 当有组件切换动效的时候，一瞬间，页面的宽度会变成 正常宽度的 2 倍，此时，需要隐藏超出屏幕宽度的区域
  overflow: hidden;
}

// 动画效果相关的类样式
.v-enter {
  opacity: 0;
  // 让即将进入的页面，向右偏移 100% 屏幕的宽度
  transform: translateX(100%);
}
.v-leave-to {
  opacity: 0;
  // 让即将进入的页面，向右偏移 100% 屏幕的宽度
  transform: translateX(-100%);
  position: absolute;
}

.v-enter-active,
.v-leave-active {
  transition: all 0.4s ease;
}

.mint-header {
  z-index: 99;
}

.mui-bar-tab .my-tab-item.mui-active {
  color: #007aff;
}

.mui-bar-tab .my-tab-item {
  display: table-cell;
  overflow: hidden;
  width: 1%;
  height: 50px;
  text-align: center;
  vertical-align: middle;
  white-space: nowrap;
  text-overflow: ellipsis;
  color: #929292;
}

.mui-bar-tab .my-tab-item .mui-icon {
  top: 3px;
  width: 24px;
  height: 24px;
  padding-top: 0;
  padding-bottom: 0;
}

.mui-bar-tab .my-tab-item .mui-icon ~ .mui-tab-label {
  font-size: 11px;
  display: block;
  overflow: hidden;
  text-overflow: ellipsis;
}
</style>
